The Paragon CZE 2000 (Beckman Analytical, Milan, Italy) is an automatic dedicated capillary zone electrophoresis (CZE) system, producing a five-zone serum protein pattern with quantitative estimation of the zones. With the view of substituting this instrument for two previously used serum protein electrophoresis techniques, we planned to produce reference values for the "new" systems leading to compatible interpretation of the results. High resolution cellulose acetate electrophoresis with visual inspection and descriptive reporting (HR-CAE) and five-zone cellulose acetate electrophoresis with densitometry (CAE-D) were the previously used techniques. Serum samples (n = 167) giving "normal pattern" with HR-CAE were assayed with the CZE system, and the results were statistically assessed to yield 0.95 reference intervals. One thousand normal and pathological serum samples were then assayed with the CAE-D and the CZE techniques, and the regression equations of the CAE-D values over the CZE values for the five zones were used to transform the CAE-D reference limits into the CZE reference limits. The two sets of reference values thereby produced were in good agreement with each other and also with reference values previously reported for the CZE system. Thus, reference values for the CZE techniques permit interpretation of results coherent with the previously used techniques and reporting modes.
This study was undertaken to evaluate the feasibility of using commercial control materials in a regional external quality assessment scheme (EQAS) for serum carcinoembryonic antigen (CEA) measurement. We have assessed the commutability of 12 commercial control materials using five automated immunochemical systems. We compared the intermethod behavior of the materials with that of 12-14 patient serum pools. In a total of 48 comparisons (12 materials x 4 pairs of analytical systems), seven instances of non-commutability were apparent, as shown by normalized residuals falling outside the +/-3 interval. The use of non-commutable materials generates two negative effects. In EQAS, the interlaboratory variation recorded is not representative of the variation expected in the assay of patient sera; in interlaboratory harmonization programs, recalibration with non-commutable materials increases, instead of decreasing, the interlaboratory variation. Both these effects were shown to occur in CEA measurement with the tested materials and systems. The materials planned to be used in our EQAS turned out to be commutable: this gave us the guarantee of measuring realistic interlaboratory variation values, although the check for commutability should be extended to all the analytical systems used by the participants in the scheme.
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In 9 patients with myeloproliferative diseases (MPD) (6 with myelofibrosis, MF, 1 with Ph1 positive chronic granulocytic leukaemia, CGL, 1 with primary eosinophilia, PE, 1 with pre‐leukaemia syndrome, preL) collagen, epinephrine, and ADP‐induced aggregation, N‐ethylmaleimide‐induced malondialdehyde (MDA) production, beta‐thromboglobulin (beta‐TG) plasma levels, and platelet turnover were studied. Collagen‐induced aggregation was found to be normal in 7 patients, absent in 1, and reduced in 1. In all but 3 patients, aggregation with ADP was markedly reduced. Epinephrine‐induced aggregation was decreased in 7 patients. No difference was found between mean MDA production in MPD (3.21 ± 0.50 nmol/109 PLTs) and in a control group of 21 normal subjects (3.04 ± 0.26 nmol/109 PLTs). Mean beta‐TG levels were significantly higher (P < 0.01) in MPD patients (165.00 ± 28.29 ng/ml) than in healthy controls (81.76 ± 14.63 ng/ml). Mean platelet production half‐time was significantly shorter in MPD (2.48 ± 0.24 d) than in the control group (3.43 ± 0.17 d), after adjustment for age by covariance analysis (P < 0.005). Our data do not indicate an abnormal prostaglandin synthesis and are consistent with the hypothesis that a disseminated intravascular platelet aggregation might take place in MPD patients.
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